Strap end holder



Oct. 23, 1962 D. P. NOEL STRAP END HOLDER Filed Aug. 12, 1960 UnitedStates atent i 3,059,300 STRAP END HOLDER Dwight P. Noel, Chester, Pa.,assignor to American Viscose Corporation, Philadelphia, Pa., acorporation of Delaware Filed Aug. 12, 1960, Ser. No. 49,303 6 Claims.(Cl. 24-434) This invention relates to strapping tools and moreparticularly to an improved strap end holding means for a straptensioning tool.

Over the years a wide variety of hand tools, some of them poweroperated, have been developed for drawing a steel strap taut about a boxor package preliminary to securing the ends of the strap together.Generally, the strap is paid out from a roll or. coil and looped aboutthe object to be strapped with the trailing portion of the strapoverlapping the leading end. With many of the tools, the leading end ofthe strap is held securely while the trailing portion is engaged by asuitable device and drawn over the leading end until the desired degreeof tension is obtained. The overlapping ends of the strap are thensecured together by any one of various means, which may be applied bythe same tool or by a separate tool, and the tailing end of the thentightly secured portion of the strap is severed from the supply.

The devices employed in steel band strapping tools for holding the endof the strap generally include a dog or pawl which is pivotallysupported from one side and provided with teeth adapted to engage thestrap and hold the same against a cooperating surface. The dog isgenerally spring urged about its pivot in engaging direction and must bemanually rocked to released position when the end of the strap is to beinserted, the strap being inserted from the side, that is, the strap imoved sidewise beneath the dog. The dog is pivoted in such a way thatits gripping action on the strap increases as the tension on the strapincreases. Either the dog itself or the member on which it is mounted isusually provided with a slot through which the trailing end of the strapis inserted so that the overlapping portions of the strap are reasonablyclose together so as to facilitate the securing together of theoverlapping portions.

While holding devices of the type referred to above are reasonablysaisfactory for use with steel band strapping, they have not provenentirely suitable for use with other type of strapping such as paper orthe more recently developed cord strapping which consists of a pluralityof cords secured together side by side in the form of a flat tape orstrap. The primary difficulty in using steel band type of end holdingdevices in tools for tightening cord strapping is that they damage thestrap, sometime to such an extent that the strap breaks or pulls out ofthe holding devices before the desired degree oftension is reached. Oneof the reasons why they damage the non-metallic strap is that because ofthe cantilever mounting of the dog, the strap is gripped more firmly onthe side adjacent the mounting of the dog, rather than uniformly acrossthe width of the strap. This is not too objectionable when using steelstrapping because the Uniform structure of the steel distributes theforce throughout the body of the strap but with cord strapping it isessential that each cord be held if the full strength of the strap is tobe realized since the pulling or tightening force cannot transfer fromone cord to another.

It is the primary object of the present invention to provide, in a straptensioning tool, an improved strap end holding means especially adaptedfor holding or gripping the end of a non-metallic strap.

It is a more specific object of the invention to provide, in a straptensioning tool, a strap end holding means which 3,059,306 Patented Oct.23, 1962 ice will not damage cord strapping or other non-metallicflexible strapping and at the same time be effective to securely holdthe same before and after the strapping is placed under full tension.

Another object of the invention is to provide a strap end holding meansof balanced construction, that is one which exerts equal pressure overthe entire holding area.

A still further object of the invention is to provide, in a straptensioning tool, a strap end holding means so constructed and arrangedthat the overlapping ends of the strap are in contact with one anotherwhereby the securing togeether of said ends is facilitated.

Another object of the invention is to provide a strap end holding meanswith which the end of the strap may be quickly engaged and from which itmay be readily released after tightening.

Other and further objects, features and advantages of the invention willbecome apparent as the description of certain preferred embodimentthereof proceeds.

Referring now to the drawing:

FIGURE 1 is a side elevational view of a strapping tool' embodying theinvention and showing its use in a strapping operation;

FIGURE 2 is a perspective view showing one form of the strap end holder;

FIGURE 3 is a sectional view taken on the line IIIIII of FIGURE 2 andshowing the strap end holder in strap holding position;

FIGURE 4 is a View similar to FIGURE 3 but showing the gripper innon-gripping position;

FIGURE 5 is a perspective view of a modified form of the invention; andi FIGURE 6 is a sectional view showing the modified form in operation.

Referring first to FIGURE 1 wherein is shown more or lessdiagrammatically one of many forms of strapping tool in which the trapend holder of the present invention may be eifectively embodied, thetool comprises generally a U-shaped frame 10 having downwardly directedlegs 11 and 12 and an integral handle 13. The tool is shown in theprocess of tightening a strap 14 about a box or package partially shownat 15 and is supported on the package by the leg 12 and a foot 16 formedintegrally with or secured to the leg 11. The strap end holding deviceis generally indicated at 17 in FIGURE 1 and the leg 12 carries themechanism for drawing the strap tight.

The strap tightening mechanism is only schematically shown inasmuch asit may take various forms and is not per se a novel feature of thepresent invention. As shown, this mechanism includes a rotatably mounteddrum 18 provided with diametric slots 19 for holding the trailing end orsome intermediate portion of the strap. A gear 20 is operativelyconnected to drum 18 and said gear is meshed with a gear 21 rotatable ona shaft 22 carried by the frame 10. An operating handle 23 is alsorotatably or swingably mounted on shaft 22 and carries an operating pawl24 which, when handle 23 is moved clockwise, causes the gear 21 torotate gear 20 and drum 18 in a direction to wind up and tighten thestrap, one end of the strap being held by the holding device 17. Aholding pawl 25 is spring urged into engagement with the gear 20 andprevents retrograde rotation of drum 18 during counterclockwise movementof handle 23. When the strap reaches the desired degree of tightness theoverlapping portions thereof are secured together by crimping a seal 26therearound. Various devices may be employed for performing the sealingoperation and as is known, such devices are frequently incorporatedin'the same tool that tightens the, strap. After application of theseal, the strap is out between the seal and drum 18 and as is alsoknown, a cutter may be incorporated in the stretching or tightening toolfor this purpose. After the strapping operation is thus completed, theoperating handle 23 is moved to its full counterclockwise positionindicated by dotted lines and the pawl 24 contacts an upstanding ear ofholding pawl 25 to thereby cause both pawls to release their respectivegears and free the drum 18.

Referring now to FIGURES 2, 3 and 4 for a detailed description of oneform of strap end holding means constructed in accordance with thepresent invention. The device comprises a main body member, which inthis case is the foot 16, and a gripper element 30 rockably mountedtherein. As shown, the main body member is formed so as to provide aslot or cavity 31 between two parallel legs 32 and 33, with leg 32 beingshorter than leg 33. A semicircular groove 34 is cut into anintermediate portion of leg 33 and a matching semicircular groove 35 iscut into the outer end of leg 32. Gripper element 30 is in the form of asolid circular cylinder and is rockably or rotatably mounted in thegrooves 34 and 35 and extends into a cylindrical opening bored into thethick portion of the body member in alignment with the grooves 34 and35. In manufacture, grooves 34 and 35 and the aligned bore in the thickportion of the body member are formed in a single drilling operation andit will be apparent that the gripper element is inserted from the rightas viewed in FIGURE 2 and cannot escape sideways from the groove 34because of the overhanging end of leg 32.

A small bore 36 is provided in the foot or main body member 16. Bore 36is transverse to and intersects the bore accommodating the inner end ofgripper element 30 and a resilient means in the form of a bent Wirespring 37 is mounted within bore 36 and engages a flat surfaced cut-out38 provided in said gripper element. Spring 37 is held in place by abent end 39 thereof which snaps into a small hole bored through thebottom of member 16 so as to intersect bore 36. Spring 37 preventsgripper element 30 from falling out endwise and serves a furtherfunction presently to be mentioned.

A portion of cylindrical gripper element 30 is cut away to form achannel 40 therein, the bottom 41 of which extends approximatelydiametrically across the cylinder. The spring 37 normally holds thegripper element in the position shown in FIGURES 2 and 4, so thatchannel 40 provides an opening between said gripper element and thelower leg 33 of the main body member.

In use, the free end of the flexible strap is inserted through theopening between the gripper element 30 and the lower leg 33 and into thecavity 31 located behind the gripper, as shown in FIGURE 4. Preferably,the surface 41 is flared away from leg 33 at the introduction side ofthe holder as indicated at 42 to facilitate the insertion of the strap.With the end of the strap thus positioned, the strap is then wrappedabout the package and the trailing portion thereof engaged with the drum18 for tightening, as previously mentioned. The act of wrapping thestrap about the package causes the strap to lie against the top of leg32 as shown in FIGURE 3 and when the strap is pulled a portion thereofengages an edge 43 of gripper element 30 and rocks said gripper againstthe action of spring 37 to cause another edge 44 to move into engagementwih the strap and pinch the same against leg 33 of the main body member.There are in reality two distinct forces which hold the end of thestrap; one, a snubbing action about the edge 43 and the end of upper leg32, and two, the squeezing or pinching force of edge 44. Thisdistributes the entire holding force in such a way that the end of thestrap is not damaged or cut.

Since gripper element 30 is supported throughout its entire length bythe main body member, the edge 44 acts uniformly across the entire faceof the strap, whereas a cantilever supported gripper, particularly whenit becomes wo'rn, will have its greatest gripping action on the sideadjacent its mounting. This uniform application of pressure all the wayacross the strap is most important when using cord or paper strapping ifthe full strength of the strap is to be utilized. Another feature of thepresent arrangement is that the overlapped portion of the strap is indirect contact with the portion adjacent the held end and thisfacilitates the application of seal 26, as will be appreciated.

That form of the invention shown in FIGURES 5 and 6 is a modification ofthat described above. In this form, the main body member consists of amember in the form of a solid circular cylinder. Member 50 is screwedinto or otherwise secured to the leg 11 of the tool and protrudesoutwardly therefrom as shown in FIGURE 5. A slot 51 is milled intomember 50 to form a cavity into which the end of the strap is inserted.Rotatably or rockably mounted upon the body member 50 is a cylindricalgripper element 52 in the form of a split sleeve having a channel 53therethrough formed by the facing end portions 54 and 55 of the sleeve.

A slot 56 is provided through gripper 52 near its inner end and saidgripper is held on body member 50 by a pin 57 extending through slot 56and screwed or otherwise secured in said body member. A spring or likeresilient means 58 is secured at one end to pin 57 and at its other endto a pin 59 extending from gripper 52. Spring 58 normally holds gripper52 in the position shown in FIGURE 5 with one end of slot 56 abuttingpin 57. In this position channel 53 is aligned with cavity 51 so thatthe end of the strap may be inserted through said channel and into saidcavity.

In that form of the invention shown in FIGURES 5 and 6, after the freeend of the strap is inserted into the holding device, the strap is ledaround the package and engaged with the drum 18 for tightening, as abovedescribed. As the strap is pulled around the package, it engages theedge portion 54 of gripper element 52 and rocks said element about bodymember 50 against the action of spring 58 whereupon the edge portion 55engages the strap and pinches it against said body member as shown inFIGURE 6 to thus securely hold the end of the strap. Since gripperelement 52 has a sliding fit with body member 50 and the edge portion 55is parallel to the slot 51, uniform pressure is applied across theentire face of the strap even though the device as a whole extendscantilever style from the leg 11. As previously mentioned, this is animportant feature of the present invention. If it is desired toeliminate the canilever construction of that form of the invention shownin FIGURES 5 and 6 and thereby increase its overall strength, the bodymember 50 may be supported at both ends, for example by making saidmember longer than sleeve 52 and securing both ends in brackets providedon a foot of the tool such as foot 16.

Having thus described certain preferred embodiments of the invention,what is claimed is:

1. In a strapping tool having means for holding one end of a flexiblestrap and means for tensioning the strap about an object; an improvedstrap end holding means comprising a stationary body member, meansproviding a cavity in said body member, a gripper element rockablymounted on said body member, means forming a channel in said gripperelement, means resiliently positioning said gripper element so that thechannei therein is aligned with the cavity in said body member wherebythe end of a strap may be inserted through the channel in said gripperelement and into the cavity in said body member, said cavity having abottom which defines the fully inserted position of the strap andthereby facilitates the proper positioning of the strap, said meansforming the channel in said gripper element having a portion adapted tobe engaged by the strap to rock said gripper element, and said meansforming the channel in said gripper element having a second portionadapted to move into contact with the strap when said element is rocked5 to pinch the strap between said element and said body member.

2. The device set forth in claim 1 wherein said gripper elementcomprises a circular cylinder and is rotatably supported throughout itslength by said body member.

3. In a strapping tool having means for holding one end of a flexiblestrap and means for tensioning the strap about an object; an improvedstrap end holding means comprising a stationary body member, a gripperelement rockably mounted on said body member, means forming an openingbetween said cripper element and said body member whereby an end of astrap may be inserted therebetween, cavity forming means in said bodymember adjacent and behind said gripper element whereby the end of thestrap may enter into the cavity after passing through the openingbetween the gripper element and body member, said cavity having a bottomwhich defines the fully inserted position of the strap and therebyfacilitates the proper positioning ofthe strap, said gripper elementhaving a first portion adapted to be engaged by the strap to rock saidelement and having a second portion adapted to move into contact withthe strap when said element is rocked to pinch the strap between saidelement and said body member, and resilient means normally holding saidgripper element in unrocked position.

4. The device set forth in claim 3 wherein said first portion of saidgripper element is flared away from said body member to facilitate theintroduction of the strap into the opening between said gripper elementand said body member.

5. The device set forth in claim 3 wherein said gripper elementcomprises a solid circular cylinder having a portion thereof cut away toprovide the opening between said element and said body member.

6. The device set forth in claim 5 wherein both ends of each cylinderare rotatably supported by said body member.

References Cited in the file of this patent UNITED STATES PATENTS730,331 Anderson June 9, 1903 1,042,529 Campbell Oct. 29, 1912 1,250,599Lee Dec. 18, 1917 1,272,944 Green July 16, 1918 1,811,738 Williams June23, 1931 2,539,333 Silbermann Jan. 23, 1951 2,557,877 Klusion June 19,1951

